User Handbook

The application is conceived with a simple and user friendly GUI, so that even less skilled users can operate it. For the application start, the QosOptimizer .jar file needs to be executed. In Microsoft Windows operating system a simple double click on the jar file will launch the application

Functional description

The QoS configuration that should be applied can be easily modified by modifying the template.txt file located in the application root directory. (mainly focusing on the ACL modifications)

Further during or before the run of the program the list of the protected flows (file: ProtectList .txt) should be modified to ensure that the chosen flows are not afflicted by the optimizing feature.

The file needs to pertain its original layout

Please put in the protocol numbers of protected flows. 
The flows have to be put in according to the transport protocol and don't forget to put "end" at the end of each protocol list.

TCP
end

UDP
end

To add a flow into the protect list. Simply choose whether it is an UDP or a TCP flow and put the destination transport port number under the corresponding transport portocol.

After executing the application the main window is displayed. The main window is simple and contains only a few controls. (Figure 1)

Figure 1: Main Window

The application first requires the user to fill in the forms in the left upper corner with the IP address of the monitored device and the responder device (used for configuring the SAA responder agent) and the read-write SNMP community strings for management access to those devices.

After the fields were filled out and the button “Discover the routers” was pressed, the application attempts to establish an SNMP session with the devices and gather data. Should the IP address or community string be invalid, a warning message is displayed informing the user that the request fro connection has timed out. In this case, please validate the IP addresses and the community strings. If the session establishment was successful, the Combo box at the right side of the main window is populated with the candidate interfaces for QoS configuration application. The user is required to select the interface he wishes to apply the QoS configuration to and enter the nominal bandwidth of the interface into the Text area underneath the combo box. The application assumes use for WAN interfaces and is conceived in that way; usage for LAN interfaces is not advised.

By selecting the interface and typing in the bandwidth, the “Apply configuration” button needs to be pressed. The button causes the routers to download and apply the generated configuration according to the data discovered by SNMP and put in by the user. If the process was unsuccessful, the application displays an error message informing the user about the possible error. In case of success the QoS configuration application phase is ended.

By pressing the “Start Monitoring” button the application advances into the monitoring phase. The charts mapping the QoS parameters over time are displayed in the left lower part of the main window (Figure 2). A connection to the BasicMeter database is established and the application starts polling the data about the QoS performance of the selected interfaces and updates the performance charts.

The first chart from the top, labeled “RTT values in time” displays the progress of round trip time samples for each class over time in milliseconds.

The second chart labeled “Utilization values in time” displays the progress of utilization pre class in bytes per second.

The last chart labeled “Drop rate in time” displays the progress of drop rate per class in amount of packets dropped per second. In the left most part, in the control text field, the actual data for the last poll are displayed pre class.

Right clicking on the displayed chart a menu for altering the display of the charts is displayed. In this menu, the charts can bee zoomed in or out, the range of both the domain and the range axis can be changed.

Figure 2: Monitoring phase

The process of changing the QoS configuration aspects to achieve dynamic optimization is hidden to the user and is executed in background. The application continues with the monitoring process until it is ended.

Eror messages

Error message: Connection Error: Receive Timed out Plausible cause: The IP addresses are entered incorrectly Solution: Validate the entered IP addresses for Router and Responder

Error message: IO Error: Receive Timed out Plausible cause: The read-write SNMP community strings were entered incorrectly Solution: Validate the entered community strings.

Error message: Input Error: Please specify the interface bandwidth Plausible cause: The interface bandwidth was not entered. Solution Enter the nominal bandwidth of the interface into the text box.

Application example

The solution might be beneficial for small networks with only a few WAN connections, where running an application instance along with the BasicMeter application on a dedicated computer at the local LAN segment of each monitored router might not pose a significant problem. In this case the identification of the aggressive flow and affecting it to ease up the congestion and in the same time managing a list of protected flows suggest a different approach to SLA enforcement in the consumer-provider environment. With the list of protected flows the consumer has the opportunity to select the traffic types in each of the configured QoS class, that should be considered as contract-violating and thus are susceptible to drops, rather than leaving the decision on which traffic is in contract and which is out of contract to the provider.

-- MartinKusnirik - 19 May 2009